[The Emerging Interest in Breast Implant Illness and its impact on Patient Behavior]. / Das wachsende Interesse an Breast Implant Illness und dessen Einfluss auf das Verhalten der Patientinnen.

Breast implant illness (BII) is a loosely defined term for a collection of non-specific systemic symptoms that are hypothesised to be associated with breast implants. BII symptoms include fatigue, hair loss, rashes, chronic pain, and others. However, conclusive evidence for a causal relationship between silicone implants and BII remains lacking. In the light of recent findings that textured implants can, in rare cases, lead to breast implant-associated anaplastic large cell lymphoma (BIA-ALCL), a potential link between breast implants and BII is conceivable and justifies further investigation. We observe a growing number of patients seeking consultation and treatment for systemic symptoms related to breast implants, which is reflected in increasing interest in literature and social media. The aim of this work was to investigate the growing interest in BII. We now describe the clinical features of a patient who suffers from symptoms that are consistent with BII and contextualise clinical presentation in a review of literature and google trend analysis.

SMC complexes can traverse physical roadblocks bigger than their ring size.

Ring-shaped structural maintenance of chromosomes (SMC) complexes like condensin and cohesin extrude loops of DNA. It remains, however, unclear how they can extrude DNA loops in chromatin that is bound with proteins. Here, we use in vitro single-molecule visualization to show that nucleosomes, RNA polymerase, and dCas9 pose virtually no barrier to loop extrusion by yeast condensin. We find that even DNA-bound nanoparticles as large as 200 nm, much bigger than the SMC ring size, also translocate into DNA loops during extrusion by condensin and cohesin. This even occurs for a single-chain version of cohesin in which the ring-forming subunits are covalently linked and cannot open to entrap DNA. The data show that SMC-driven loop extrusion has surprisingly little difficulty in accommodating large roadblocks into the loop. The findings also show that the extruded DNA does not pass through the SMC ring (pseudo)topologically, hence pointing to a nontopological mechanism for DNA loop extrusion.

A Rapid, Highly Sensitive and Open-Access SARS-CoV-2 Detection Assay for Laboratory and Home Testing.

RT-qPCR-based diagnostic tests play important roles in combating virus-caused pandemics such as Covid-19. However, their dependence on sophisticated equipment and the associated costs often limits their widespread use. Loop-mediated isothermal amplification after reverse transcription (RT-LAMP) is an alternative nucleic acid detection method that overcomes these limitations. Here, we present a rapid, robust, and sensitive RT-LAMP-based SARS-CoV-2 detection assay. Our 40-min procedure bypasses the RNA isolation step, is insensitive to carryover contamination, and uses a colorimetric readout that enables robust SARS-CoV-2 detection from various sample types. Based on this assay, we have increased sensitivity and scalability by adding a nucleic acid enrichment step (Bead-LAMP), developed a version for home testing (HomeDip-LAMP), and identified open-source RT-LAMP enzymes that can be produced in any molecular biology laboratory. On a dedicated website, rtlamp.org (DOI: 10.5281/zenodo.6033689), we provide detailed protocols and videos. Our optimized, general-purpose RT-LAMP assay is an important step toward population-scale SARS-CoV-2 testing.

Bleeding Risk Assessment in End-Stage Kidney Disease: Validation of Existing Risk Scores and Evaluation of a Machine Learning-Based Approach.

BACKGROUND: Patients with end-stage kidney disease (ESKD) on hemodialysis (HD) are at increased risk for bleeding. However, despite relevant clinical implications regarding dialysis modalities or anticoagulation, no bleeding risk assessment strategy has been established in this challenging population. METHODS: Analyses on bleeding risk assessment models were performed in the population-based Vienna InVestigation of Atrial fibrillation and thromboemboLism in patients on hemoDialysIs (VIVALDI) study including 625 patients. In this cohort study, patients were prospectively followed for a median observation period of 3.5 years for the occurrence of major bleeding. First, performances of existing bleeding risk scores (i.e., HAS-BLED, HEMORR2HAGES, ATRIA, and four others) were evaluated in terms of discrimination and calibration. Second, four machine learning-based prediction models that included clinical, dialysis-specific, and laboratory parameters were developed and tested using Monte Carlo cross-validation. RESULTS: Of 625 patients (median age: 66 years, 37% women), 89 (14.2%) developed major bleeding, with a 1-year, 2-year, and 3-year cumulative incidence of 6.1% (95% confidence interval [CI]: 4.2-8.0), 10.3% (95% CI: 8.0-12.8), and 13.5% (95% CI: 10.8-16.2), respectively. C-statistics of the seven contemporary bleeding risk scores ranged between 0.54 and 0.59 indicating poor discriminatory performance. The HAS-BLED score showed the highest C-statistic of 0.59 (95% CI: 0.53-0.66). Similarly, all four machine learning-based predictions models performed poorly in internal validation (C-statistics ranging from 0.49 to 0.55). CONCLUSION: Existing bleeding risk scores and a machine learning approach including common clinical parameters fail to assist in bleeding risk prediction of patients on HD. Therefore, new approaches, including novel biomarkers, to improve bleeding risk prediction in patients on HD are needed.

Prolonged antibiotic prophylaxis in tissue reconstruction using autologous fat grafting: Is there a benefit for wound healing?

Fat grafting is a well-established method in plastic surgery. Despite many technical advances, standardised recommendations for the use of prophylactic antibiotics in fat grafting are not available. This retrospective multicentre study aims to analyse the use of prophylactic antibiotics in fat grafting and to compare complication rates for different protocols. A retrospective medical chart review of 340 patients treated with fat grafting of the breast from January 2007 to March 2019 was performed in three plastic surgery centres. Complications, outcomes, and antibiotic regimes were analysed. The Clavien-Dindo classification was applied. All patients received perioperative antibiotic prophylaxis: 33.8% (n = 115) were treated with a single shot (group 1), 66.2% (n = 225) received a prolonged antibiotic scheme (group 2). There was no significant difference in the number of sessions (P = .475). The overall complication rate was 21.6% (n = 75), including graft resorption, fat necrosis, infection, and wound healing problems. Complication rates were not significantly different between groups. Risk factors for elevated complication rates in this specific patient group are smoking, chemotherapy, and irradiation therapy. The complication rate for lipografting of the breast is low, and it is not correlated to the antibiotic protocol. The use of prolonged prophylactic antibiotics does not lower the complication rate.

Zebrafish Embryos and Larvae as Alternative Animal Models for Toxicity Testing.

Prerequisite to any biological laboratory assay employing living animals is consideration about its necessity, feasibility, ethics and the potential harm caused during an experiment. The imperative of these thoughts has led to the formulation of the 3R-principle, which today is a pivotal scientific standard of animal experimentation worldwide. The rising amount of laboratory investigations utilizing living animals throughout the last decades, either for regulatory concerns or for basic science, demands the development of alternative methods in accordance with 3R to help reduce experiments in mammals. This demand has resulted in investigation of additional vertebrate species displaying favourable biological properties. One prominent species among these is the zebrafish (Danio rerio), as these small laboratory ray-finned fish are well established in science today and feature outstanding biological characteristics. In this review, we highlight the advantages and general prerequisites of zebrafish embryos and larvae before free-feeding stages for toxicological testing, with a particular focus on cardio-, neuro, hepato- and nephrotoxicity. Furthermore, we discuss toxicokinetics, current advances in utilizing zebrafish for organ toxicity testing and highlight how advanced laboratory methods (such as automation, advanced imaging and genetic techniques) can refine future toxicological studies in this species.

Cohesin mediates DNA loop extrusion by a "swing and clamp" mechanism.

Structural maintenance of chromosomes (SMC) complexes organize genome topology in all kingdoms of life and have been proposed to perform this function by DNA loop extrusion. How this process works is unknown. Here, we have analyzed how loop extrusion is mediated by human cohesin-NIPBL complexes, which enable chromatin folding in interphase cells. We have identified DNA binding sites and large-scale conformational changes that are required for loop extrusion and have determined how these are coordinated. Our results suggest that DNA is translocated by a spontaneous 50 nm-swing of cohesin's hinge, which hands DNA over to the ATPase head of SMC3, where upon binding of ATP, DNA is clamped by NIPBL. During this process, NIPBL "jumps ship" from the hinge toward the SMC3 head and might thereby couple the spontaneous hinge swing to ATP-dependent DNA clamping. These results reveal mechanistic principles of how cohesin-NIPBL and possibly other SMC complexes mediate loop extrusion.

Keystone Flap Type IIIB: A New Variation for Coverage of Defects at Joint Regions.

Soft tissue defect reconstruction at joint regions is a challenging problem due to the sparse excessive tissue and late complication of constrigent scar formation. Priorly irradiated tissue, often the case in sarcoma patients, is especially problematic. The keystone design perforator island flap is safe and reliable. We now present a new keystone flap design, which is particularly suitable for the reconstruction of large soft tissue defects at joint regions. It provides a cutaneous component without the need for a skin graft and therefore minimizes the risk of contracture. Donor site morbidity is negligible. Furthermore, it offers a favorable aesthetic result compared to other flaps, eg, a muscular flap. We propose a new keystone flap design as an extension of Behan's classification, the Keystone flap type IIIb.

Exploration of zebrafish larvae as an alternative whole-animal model for nephrotoxicity testing.

Due to an increasing demand for testing of new and existing chemicals and legal restrictions for the use of animals, there is a strong need for alternative approaches to assess systemic toxicity. Embryonic and larval zebrafish (Danio rerio) are increasingly recognized as a promising alternative whole-animal model that may be able to overcome limitations of cell-based in vitro assays and bridge the gap between high-throughput in vitro screening and low-throughput in vivo tests in animals. Despite the relatively simple anatomical structure of the zebrafish larval kidney (pronephros) - composed of only two nephrons - the pronephros shares major functions and cell types with mammalian nephrons. Glomerular filtration begins at 48 h post fertilization. The aim of the present study was to investigate if early zebrafish larvae might be a suitable model for nephrotoxicity testing. On day 3 post fertilization, larval zebrafish were treated with selected nephrotoxins (aristolochic acid, cadmium chloride, potassium bromate, ochratoxin A, gentamicin) for 48 h. Histological evaluation of zebrafish larvae exposed to model nephrotoxins revealed tubule injury as evidenced by dilated tubules with loss of the brush border, tubule cell necrosis and disorganization of the tubular epithelium. These changes were most severe after treatment with gentamicin, which also impaired pronephros function as evidenced by reduced clearance of FITC-dextran. Whole-mount in situ hybridization showing loss of cdh17 expression revealed site-specific injury to the proximal tubule segment. Analysis of genes previously identified as novel biomarkers of kidney injury in mammals showed upregulation of the kidney injury marker genes heme oxygenase 1 (hmox1), clusterin (clu), secreted phosphoprotein/osteopontin (spp1), connective tissue growth factor (ctgf) and kim-1 (havcr-1) in response to nephrotoxin treatment, although the response of individual genes varied across compounds. Consistent with the severity of lesions and impaired kidney function, the most prominent gene expression changes occurred in larvae exposed to gentamicin. Overall, our results suggest that larval zebrafish may be a suitable alternative model organism for nephrotoxicity screening, yet further improvements and integration with quantitative in vitro to in vivo extrapolation will be needed to predict human toxicity.

Quantifying the heterogeneity of macromolecular machines by mass photometry.

Sample purity is central to in vitro studies of protein function and regulation, and to the efficiency and success of structural studies using techniques such as x-ray crystallography and cryo-electron microscopy (cryo-EM). Here, we show that mass photometry (MP) can accurately characterize the heterogeneity of a sample using minimal material with high resolution within a matter of minutes. To benchmark our approach, we use negative stain electron microscopy (nsEM), a popular method for EM sample screening. We include typical workflows developed for structure determination that involve multi-step purification of a multi-subunit ubiquitin ligase and chemical cross-linking steps. When assessing the integrity and stability of large molecular complexes such as the proteasome, we detect and quantify assemblies invisible to nsEM. Our results illustrate the unique advantages of MP over current methods for rapid sample characterization, prioritization and workflow optimization.

DNA loop extrusion by human cohesin.

Eukaryotic genomes are folded into loops and topologically associating domains, which contribute to chromatin structure, gene regulation, and gene recombination. These structures depend on cohesin, a ring-shaped DNA-entrapping adenosine triphosphatase (ATPase) complex that has been proposed to form loops by extrusion. Such an activity has been observed for condensin, which forms loops in mitosis, but not for cohesin. Using biochemical reconstitution, we found that single human cohesin complexes form DNA loops symmetrically at rates up to 2.1 kilo-base pairs per second. Loop formation and maintenance depend on cohesin's ATPase activity and on NIPBL-MAU2, but not on topological entrapment of DNA by cohesin. During loop formation, cohesin and NIPBL-MAU2 reside at the base of loops, which indicates that they generate loops by extrusion. Our results show that cohesin and NIPBL-MAU2 form an active holoenzyme that interacts with DNA either pseudo-topologically or non-topologically to extrude genomic interphase DNA into loops.

Protein translocation by the SecA ATPase occurs by a power-stroke mechanism.

SecA belongs to the large class of ATPases that use the energy of ATP hydrolysis to perform mechanical work resulting in protein translocation across membranes, protein degradation, and unfolding. SecA translocates polypeptides through the SecY membrane channel during protein secretion in bacteria, but how it achieves directed peptide movement is unclear. Here, we use single-molecule FRET to derive a model that couples ATP hydrolysis-dependent conformational changes of SecA with protein translocation. Upon ATP binding, the two-helix finger of SecA moves toward the SecY channel, pushing a segment of the polypeptide into the channel. The finger retracts during ATP hydrolysis, while the clamp domain of SecA tightens around the polypeptide, preserving progress of translocation. The clamp opens after phosphate release and allows passive sliding of the polypeptide chain through the SecA-SecY complex until the next ATP binding event. This power-stroke mechanism may be used by other ATPases that move polypeptides.

Exact numerical calculation of fixation probability and time on graphs.

The Moran process on graphs is a popular model to study the dynamics of evolution in a spatially structured population. Exact analytical solutions for the fixation probability and time of a new mutant have been found for only a few classes of graphs so far. Simulations are time-expensive and many realizations are necessary, as the variance of the fixation times is high. We present an algorithm that numerically computes these quantities for arbitrary small graphs by an approach based on the transition matrix. The advantage over simulations is that the calculation has to be executed only once. Building the transition matrix is automated by our algorithm. This enables a fast and interactive study of different graph structures and their effect on fixation probability and time. We provide a fast implementation in C with this note (Hindersin et al., 2016). Our code is very flexible, as it can handle two different update mechanisms (Birth-death or death-Birth), as well as arbitrary directed or undirected graphs.

Epitaxial Growth of Room-Temperature Ferromagnetic MnAs Segments on GaAs Nanowires via Sequential Crystallization.

We investigate the incorporation of manganese into self-catalyzed GaAs nanowires grown in molecular beam epitaxy. Our study reveals that Mn accumulates in the liquid Ga droplet and that no significant incorporation into the nanowire is observed. Using a sequential crystallization of the droplet, we then demonstrate a deterministic and epitaxial growth of MnAs segments at the nanowire tip. This technique may allow the seamless integration of multiple room-temperature ferromagnetic segments into GaAs nanowires with high-crystalline quality.

Which risk scenarios can drive the emergence of costly cooperation?

In collective risk dilemmas, cooperation prevents collective loss only when players contribute sufficiently. In these more complex variants of a social dilemma, the form of the risk curve is crucial and can strongly affect the feasibility of a cooperative outcome. The risk typically depends on the sum of all individual contributions. Here, we introduce a general approach to analyze the stabilization of cooperation under any decreasing risk curve and discuss how different risk curves affect cooperative outcomes. We show that the corresponding solutions can be reached by social learning or evolutionary dynamics. Furthermore, we extend our analysis to cases where individuals do not only care about their expected payoff, but also about the associated distribution of payoffs. This approach is an essential step to understand the effects of risk decay on cooperation.

Mitochondrial DNA and Toll-Like Receptor-9 Are Associated With Mortality in Critically Ill Patients.

OBJECTIVES: Despite underlying pathologies leading to ICU admittance are heterogeneous, many patients develop a systemic inflammatory response syndrome often in the absence of microbial pathogens. Mitochondrial DNA that shows similarities to bacterial DNA may be released after tissue damage and activates the innate immune system by binding to toll-like receptor-9 on immune cells. The aim of this study was to analyze whether levels of mitochondrial DNA are associated with 30-day survival and whether this predictive value is modified by the expression of its receptor toll-like receptor-9. DESIGN: Single-center, prospective, observational study. SETTING: A tertiary ICU in a university hospital. PATIENTS: Two hundred twenty-eight consecutive patients admitted to a medical ICU between August 2012 and August 2013. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Blood was taken within 24 hours after ICU admission, and the levels of circulating mitochondrial DNA were quantified by real-time polymerase chain reaction. Toll-like receptor-9 expression in monocytes was measured by flow cytometry. Median acute physiology and chronic health evaluation II score was 20, and 30-day mortality was 25%. Median mitochondrial DNA levels at admission were significantly higher in nonsurvivors when compared with survivors (26.9, interquartile range = 11.2-60.6 ng/mL vs 19.7, interquartile range = 9.5-34.8 ng/mL; p < 0.05). Patients with plasma levels of mitochondrial DNA in the highest quartile (mitochondrial DNA > 38.2 ng/mL) had a 2.6-fold higher risk (p < 0.001) of dying, independently of age, gender, diagnosis, and acute physiology and chronic health evaluation II score. Mitochondrial DNA improved the c-statistic of acute physiology and chronic health evaluation II score (p < 0.05) and showed enhancement in individual risk prediction indicated by a net reclassification improvement of 32.3% (p < 0.05). Stratification of patients according to toll-like receptor-9 expression above/below median demonstrated that only patients with high expression of toll-like receptor-9 showed an increased risk associated with increased mitochondrial DNA levels (odds ratio, 2.7; p < 0.01), whereas circulating mitochondrial DNA was not associated with mortality in patients with low toll-like receptor-9 expression (odds ratio, 1.1; p = 0.98). CONCLUSIONS: Circulating levels of mitochondrial DNA at ICU admission predict mortality in critically ill patients. This association was in particular present in patients with elevated toll-like receptor-9 expression.

Sequential karyotyping in Burkitt lymphoma reveals a linear clonal evolution with increase in karyotype complexity and a high frequency of recurrent secondary aberrations.

Typical Burkitt lymphoma is characterized by an IG-MYC translocation and overall low genomic complexity. Clinically, Burkitt lymphoma has a favourable prognosis with very few relapses. However, the few patients experiencing disease progression and/or relapse have a dismal outcome. Here we report cytogenetic findings of seven cases of Burkitt lymphoma in which sequential karyotyping was performed at time of diagnosis and/or disease progression/relapse(s). After case selection, karyotype re-review and additional molecular analyses were performed in six paediatric cases, treated in Berlin-Frankfurt-Münster-Non-Hodgkin lymphoma study group trials, and one additional adult patient. Moreover, we analysed 18 cases of Burkitt lymphoma from the Mitelman database in which sequential karyotyping was performed. Our findings show secondary karyotypes to have a significant increase in load of cytogenetic aberrations with a mean number of 2, 5 and 8 aberrations for primary, secondary and third investigations. Importantly, this increase in karyotype complexity seemed to result from recurrent secondary chromosomal changes involving mainly trisomy 21, gains of 1q and 7q, losses of 6q, 11q, 13q, and 17p. In addition, our findings indicate a linear clonal evolution to be the predominant manner of cytogenetic evolution. Our data may provide a biological framework for the dismal outcome of progressive and relapsing Burkitt lymphoma.

Repeatability of evolution on epistatic landscapes.

Evolution is a dynamic process. The two classical forces of evolution are mutation and selection. Assuming small mutation rates, evolution can be predicted based solely on the fitness differences between phenotypes. Predicting an evolutionary process under varying mutation rates as well as varying fitness is still an open question. Experimental procedures, however, do include these complexities along with fluctuating population sizes and stochastic events such as extinctions. We investigate the mutational path probabilities of systems having epistatic effects on both fitness and mutation rates using a theoretical and computational framework. In contrast to previous models, we do not limit ourselves to the typical strong selection, weak mutation (SSWM)-regime or to fixed population sizes. Rather we allow epistatic interactions to also affect mutation rates. This can lead to qualitatively non-trivial dynamics. Pathways, that are negligible in the SSWM-regime, can overcome fitness valleys and become accessible. This finding has the potential to extend the traditional predictions based on the SSWM foundation and bring us closer to what is observed in experimental systems.

Conformational Changes of the Clamp of the Protein Translocation ATPase SecA.

Post-translational protein translocation across the bacterial plasma membrane is mediated by the interplay of the SecA ATPase and the protein-conducting SecY channel. SecA consists of several domains, including two nucleotide-binding domains (NBD1 and NBD2), a polypeptide cross-linking domain (PPXD), a helical scaffold domain (HSD), and a helical wing domain (HWD). PPXD, HSD, and NBD2 form a clamp that positions the polypeptide substrate above the channel so that it can be pushed into the channel by a two-helix finger of the HSD. How the substrate is accommodated in the clamp during translocation is unclear. Here, we report a crystal structure of Thermotoga maritima SecA at 1.9 Å resolution. Structural analysis and free-energy calculations indicate that the new structure represents an intermediate state during the transition of the clamp from an open to a closed conformation. Molecular dynamics simulations show that closure of the clamp occurs in two phases, an initial movement of PPXD, HSD, and HWD as a unit, followed by a movement of PPXD alone toward NBD2. Simulations in the presence of a polypeptide chain show that the substrate associates with the back of the clamp by dynamic hydrogen bonding and that the clamp is laterally closed by a conserved loop of the PPXD. Mutational disruption of clamp opening or closure abolishes protein translocation. These results suggest how conformational changes of SecA allow substrate binding and movement during protein translocation.

Decatransin, a new natural product inhibiting protein translocation at the Sec61/SecYEG translocon.

A new cyclic decadepsipeptide was isolated from Chaetosphaeria tulasneorum with potent bioactivity on mammalian and yeast cells. Chemogenomic profiling in S. cerevisiae indicated that the Sec61 translocon complex, the machinery for protein translocation and membrane insertion at the endoplasmic reticulum, is the target. The profiles were similar to those of cyclic heptadepsipeptides of a distinct chemotype (including HUN-7293 and cotransin) that had previously been shown to inhibit cotranslational translocation at the mammalian Sec61 translocon. Unbiased, genome-wide mutagenesis followed by full-genome sequencing in both fungal and mammalian cells identified dominant mutations in Sec61p (yeast) or Sec61α1 (mammals) that conferred resistance. Most, but not all, of these mutations affected inhibition by both chemotypes, despite an absence of structural similarity. Biochemical analysis confirmed inhibition of protein translocation into the endoplasmic reticulum of both co- and post-translationally translocated substrates by both chemotypes, demonstrating a mechanism independent of a translating ribosome. Most interestingly, both chemotypes were found to also inhibit SecYEG, the bacterial Sec61 translocon homolog. We suggest 'decatransin' as the name for this new decadepsipeptide translocation inhibitor.